During a five-month long effort to get in shape to drive in the Indianapolis 500 and Coca-Cola 600 on the Sunday before Memorial Day, when his body seemed like it wasn't going to let him do another pull-up or bear another weight, Kurt Busch would think about the day he met a now 32-year-old Marine staff sergeant named Liam Dwyer.

Or, rather, the day Dwyer called him out.

This was in October of 2012, during a routine visit to Walter Reed National Military Medical Center in Bethesda, Md. Busch had nearly finished making his rounds in the physical therapy room—signing autographs, posing for selfies and making pleasant conversation—when a voice at the back of the room bellowed, "Hey Busch! Come here!"

Startled but curious, Busch advanced toward the thick, phlegmy baritone and found a one-legged man with a frail right arm doing curls with a stress ball.

"You ever race any go-karts?" Dwyer asked, staring at Busch while laboring to restore the strength and feeling in an arm that was damaged after he stepped on an explosive device on May 22, 2011 while searching a compound during a tour of Afghanistan. The blast, which severely injured Dwyer's right arm and leg, also sheared his left leg off above the knee. What's more, this happened four years after Dwyer escaped certain death in Iraq while working as the turret gunner of a Humvee that was hit by a roadside bomb—an explosion that sent a shower of shrapnel into the left side of his body.

"I do some go-kart racing every now and then," Busch replied.

"Alright, well, when we get together I'm gonna kick your ass," Dwyer said.

With that, the two traded numbers and made a promise to continue their conversation on a track. And while much about Dwyer's boast remains unsettled even though the two men have raced each other once—at Autobahn Speedway in Jessup, Md., one of Busch's favorite circuits, in January of 2013—they can at least agree that racing is one of the most physically demanding sports. And when your body has been broken by the trials of war or other misfortune, those demands could fill a hundred haulers.

As much as a racer's experiences sitting behind a wheel might resemble those of the average license-carrying driver, the feeling couldn't be more different. The steering is weighted, the cockpit is hot and cramped, and the G-forces are tremendous for hours at a time.

Busch's thrice weekly karate boot camp seemed like a grind until Dwyer started describing the four-to-five hours of daily physical therapy he had to endure just to resume a halfway normal life. To pursue a passion for racing that dates to his days growing up in Waterbury, Ct., Dwyer knew that he'd have to work even harder.

"I had to maintain my strength to keep the car in good position," says Dwyer, adding that he wasn't much of a gym rat during his military career, but he has become one as a racer. "I started focusing on dips, crunches, leg lifts, push-ups, and endurance stuff—walking. Reason being, at the track, I knew I didn't want to be in my wheelchair. I wanted to be able to walk around and show people how far I've come and what I can do."

After a successful test earlier this year, Freedom Autosport brought Dwyer on to run select rounds of the IMSA Continental Tire SportsCar Challenge series. While his standard issue prosthetic lower leg was plenty good enough for pacing around the garage and the pits, it was almost useless inside the cockpit—where the absence of his natural lower leg joints became most conspicuous during gear changes.

"Being that this is endurance racing, where we do driver changes, I still have to operate a manual transmission," Dwyer says. "We needed to keep my foot firmly attached to the clutch, but also have it be able to quickly disengage and get me out of the car very quickly."

So Dwyer and his team came up with a few changes. First, they MacGyver'd a coupling system—using a bracket and some Velcro—that keeps his left leg in constant contact with clutch pedal and also allows him to be rapidly extricated from the car. Then, Dwyer switched his "clutch leg" to one with a biomechanical knee. "This way we don't have to worry about my leg dying on me," he says. "The biomechanical leg uses a battery, and even though it last for days, there are times when I just forget to charge it.

"When you get going with travel, it can be quite difficult to get your leg charged up at night. The last thing you want to be is in the car and have the leg not be charged to where it can't operate or bend. And if that's the case, then my foot gets pinned to the clutch and I can't operate the clutch anymore."

That was not the case on the Saturday before Memorial Day, during a 2.5-hour International Motor Sports Association race at Lime Rock Park in Connecticut. Dwyer turned the first 22 laps before yielding Freedom's No. 27 Mazda MX-5 to co-driver Tom Long, who took the lead five laps from the end and cruised to a nearly 20-second victory. That it would come on Dwyer's home track, within two days of the three-year anniversary of his avoiding death—his "alive day," he calls it—was all the sweeter.

Cycle of salvation

Photo: Courtesy of Ryan Smith/SI

From the depths of despair, wounded veteran Jesse Williamson is rising to stardom in his sport.

Now comes Jesse Williamson's turn to make his mark at the Baja 500, a four-day, 500-mile race through the Mexican desert that will end on Sunday, June 8. Two years before Dwyer's Afghanistan tour, Williamson, a 25-year-old lance corporal, was there, sitting in the turret seat of a Humvee when an I.E.D struck. The impact shot him 60 feet into the air and killed everyone inside the vehicle. Had a Marine in a trailing Humvee not moved quickly to collect Williamson and get him to safety, the body count might've been eight.

Still, in Williamson's initial view, there seemed little point in living if he couldn't have full use of his legs. After 60 or so surgeries failed to get him back on his feet, he consented to a double amputation, just below the knees. But it damn near crushed him. He moved back home to Monroe, Wash., got addicted to painkillers, then graduated to heroin and became a poster child for Post Traumatic Stress Disorder. "For the longest time I didn't believe I had it," he says.

That's when another Marine came to his rescue: active First Sergeant Nick Hamm. The two met while Williamson was rehabbing at a military hospital in San Diego. Like Williamson, Hamm had been struck by an I.E.D while riding in a Humvee. He went through all the requisite depression cycles even though he had emerged relatively unscathed physically. During those dark times, a motorcycle hobby had been his only salvation.

Williamson, who had been racing bikes since he was 9, seemed like an ideal talent to build a team around. When word of his descent into depression reached Hamm in 2012, he insisted that Williamson come live with him in San Diego even though Hamm's wife was seven months pregnant with their first child.

"She had to deal with a lot of my struggles and withdrawals," Williamson says. "I relapsed twice down here, ran away from home. I was also happy that someone did care enough to keep coming to get me because for the longest time I stopped caring about myself."

That changed after Hamm turned the crew of combat veterans with whom he built motorcycles on weekends into a full-fledged racing team—Warrior Built—and Williamson became their ace rider. He kicked his heroin habit (he's now 10 months clean) and began CrossFit training with motocross pro Ryan Hughes.

"Breathing is the big [concern]," Williamson says. "Riding for that long and putting your muscles through all that stress, you have to have the endurance." (VIDEO)

Williamson also needs special prostheses—"motolegs," he calls them—which are like ski boots, but with shock absorbers inside. They make for smooth operating, until the bike stalls out. "Then I've got to get off the bike and lean it up against a tree or something to get it going again," he says, "because I don't have an ankle or anything to kinda push myself up those couple extra inches. If I'm lucky I'll be going down a hill and I could just ride it down and kick it over."

To spare Williamson some of this work, he has had his bike fitted with an automatic shift and a handlebar-mounted rear brake lever for improved stationary stability. (Funding for the upgrades came in part from Monster energy drinks, a sponsor he and Busch have in common.) Not that Williamson needed the modifications in April's Imperial 250. His three-man team finished the SoCal desert race second in their class. Barely two-thirds of the entrants finish at all.

As badly as Williamson wants to win the Baja, he's happy enough to have a mission again. "I don't want to just do this just for myself," he says. "I've tried to do it for myself before and it didn't really work out too well. I'm trying to do this for the brothers that I lost [in combat] and to help as many combat veterans and guys who are struggling as well. And not just here in the United States. There are other countries fighting wars. If I can inspire those other guys in other countries to get out of their house and try to deal with their PTSD or whatever they're going through in a more healthy way, then that's what I want to do."

A big reason why Busch chose to run the double this year was to raise awareness of the issues that wounded warriors like Dwyer and Williamson deal with on a daily basis. But some guys don't need a lift from Busch. They just need their own ride. Thanks to the new lease on life that racing has given them, Dwyer and Williamson are managing just fine on their own.

In fact, the time Busch spent with Dwyer on the go-kart track in January of last year was more fuel to draw upon during his long afternoons at the dojo.

"We went to the go-kart track and he put up a good fight," says Busch. "I took it to him. I mean, I'm the pro! But it was fun to race with him and feel that energy from him, from that rehab moment when we were together in that room. He used that motivation to get through it. Now he's racing with me. He can go back and tell his brothers in the military that Kurt was a man of his word, that he was there, and that there was inspiration received from both sides."